<template>
  <div class="app-container">
    <h2 style="text-align: center;">发布新课程</h2>

    <el-steps
      :active="1"
      process-status="wait"
      align-center
      style="margin-bottom: 40px;"
    >
      <el-step title="填写课程基本信息" />
      <el-step title="创建课程大纲" />
      <el-step title="提交审核" />
    </el-steps>
    <el-form label-width="120px">
      <el-form-item label="课程标题">
        <el-input
          v-model="courseInfo.title"
          placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"
        />
      </el-form-item>

      <!-- 所属分类 TODO -->

      <!-- 所属分类：级联下拉列表 -->
      <!-- 一级分类 -->
      <el-form-item label="课程类别">
        <el-select
          v-model="courseInfo.subjectParentId"
          placeholder="一级分类"
          @change="subjectLevelOneChanged"
        >
          <el-option
            v-for="subject in subjectNestedList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"
          />
        </el-select>
        <!-- 二级分类 -->
        <el-select v-model="courseInfo.subjectId" placeholder="二级分类">
          <el-option
            v-for="subject in subSubjectList"
            :key="subject.value"
            :label="subject.title"
            :value="subject.id"
          />
        </el-select>
      </el-form-item>

      <!-- 课程讲师 TODO -->
      <el-form-item label="课程讲师">
        <el-select v-model="courseInfo.teacherId" placeholder="请选择">
          <el-option
            v-for="teacher in teacherList"
            :key="teacher.id"
            :label="teacher.name"
            :value="teacher.id"
          />
        </el-select>
      </el-form-item>

      <el-form-item label="总课时">
        <el-input-number
          :min="0"
          v-model="courseInfo.lessonNum"
          controls-position="right"
          placeholder="请填写课程的总课时数"
        />
      </el-form-item>

      <!-- 课程简介 TODO -->
      <el-form-item label="课程简介">
        <el-input v-model="courseInfo.description" placeholder="" />
      </el-form-item>
      <!-- 课程封面 TODO -->
      <!-- 课程封面-->
      <el-form-item label="课程封面">
        <el-upload
          :show-file-list="false"
          :on-success="handleAvatarSuccess"
          :before-upload="beforeAvatarUpload"
          :action="BASE_API + '/eduoss/fileoss/upload'"
          class="avatar-uploader"
        >
          <img :src="courseInfo.cover" />
        </el-upload>
      </el-form-item>

      <el-form-item label="课程价格">
        <el-input-number
          :min="0"
          v-model="courseInfo.price"
          controls-position="right"
          placeholder="免费课程请设置为0元"
        />
        元
      </el-form-item>

      <el-form-item>
        <el-button
          :disabled="saveBtnDisabled"
          type="primary"
          @click="saveOrUpdate"
          >保存并下一步</el-button
        >
      </el-form-item>
    </el-form>
  </div>
</template>
<script>
import course from "@/api/edu/course.js";
import subject from "@/api/edu/subject.js";

export default {
  data() {
    return {
      saveBtnDisabled: false, // 保存按钮是否禁用
      courseInfo: {
        title: "",
        subjectId: "",
        subjectParentId: "",
        teacherId: "",
        lessonNum: 0,
        description: "",
        cover: "/static/01.jpg",
        price: 0
      },
      BASE_API: process.env.BASE_API, // 接口API地址
      teacherList: [],
      subjectNestedList: [], //一级分类列表
      subSubjectList: [] //二级分类列表
    };
  },

  created() {
    console.log("info created");
    this.getTeacherList();
    this.getAllSubject();
  },

  methods: {
    //上传成功之前调用的方法
    beforeAvatarUpload(file) {
      const isJPG = file.type === "image/jpeg";
      const isLt2M = file.size / 1024 / 1024 < 2;

      if (!isJPG) {
        this.$message.error("上传头像图片只能是 JPG 格式!");
      }
      if (!isLt2M) {
        this.$message.error("上传头像图片大小不能超过 2MB!");
      }
      return isJPG && isLt2M;
    },

    //上传成功之后调用的方法
    handleAvatarSuccess(res, file) {
      console.log(res); // 上传响应
      console.log(URL.createObjectURL(file.raw)); // base64编码
      this.courseInfo.cover = res.data.url;
    },

    subjectLevelOneChanged(value) {
      console.log(value);
      for (let i = 0; i < this.subjectNestedList.length; i++) {
        if (this.subjectNestedList[i].id === value) {
          //每次选择一级分类都将二级分类的值清空
          this.subSubjectList = this.subjectNestedList[i].children;
          this.courseInfo.subjectId = "";
        }
      }
    },

    getAllSubject() {
      subject
        .getSubjectList()
        .then(response => {
          this.subjectNestedList = response.data.list;
        })
        .catch(error => {});
    },

    getTeacherList() {
      course.getTeacherList().then(response => {
        this.teacherList = response.data.items;
      });
    },

    saveOrUpdate() {
      course.getSubjectList(this.courseInfo).then(response => {
        this.$message({
          type: "success",
          message: "保存成功!"
        });
        console.log(this.courseInfo);
        this.$router.push({
          path: "/course/chapter/" + response.data.eduCourseId
        });
      });
    }
  }
};
</script>